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BIG PHYSICS, BIG QUESTIONS –

Killer virus piles on the misery in Zaire

By Debora MacKenzie

MONKEYPOX, a rare and potentially fatal virus caught from rodents, is
spreading through war-torn central Zaire. For the first time, humans are
transmitting the disease to each other. Scientists studying the
outbreak—who have since been chased out by soldiers—fear it could
become widespread.

Until now, the only known human cases of monkeypox were sporadic, and were
transmitted to humans by squirrels and other rodents. Its symptoms resemble
smallpox, and include fever, cough and crusted pustules on the skin. When last
studied in the 1980s, 10 per cent of infections were fatal, mainly among
children. Only 37 cases were found in a survey carried out between 1981 and
1986, says Yvan Hutin of the US Centers for Disease Control and Prevention (CDC)
in Atlanta.

But since last July, there have been at least 163 cases in Eastern Kasai
province in Zaire, the largest cluster ever reported. A team from the CDC, the
European Union and the WHO surveyed 12 villages in February and found monkeypox
in 2 per cent of the villagers.

The researchers believe the disease may have become established after
smallpox vaccinations ceased more than 15 years ago. The vaccinia virus used in
the smallpox vaccine protects against monkeypox, as would exposure to smallpox
itself. Both are now absent for the first time since smallpox evolved, and a
vulnerable population is now developing, says Hutin. He adds that it may be
necessary to start vaccinating people in the region against smallpox to prevent
monkeypox from spreading further.

The critical thing, according to Hutin, is “whether the virus can now
maintain itself within a human population, without there also being lots of
people around who are catching it from animals. We don’t know whether one
infected person could go to Kinshasa and start an epidemic.” The UN Department
of Humanitarian Affairs warns that the continued movement of refugees in the
region could help spread the virus.